can1357
09aa87103c
- Added write-token generation and validation to distinguish writable and read-only guests. - Added deep-link support using `https://<relay>/#<link>` with 32/48-byte collab secrets. - Added full-link and key-only semantics where full links grant writes and key-only links are view-only. - Added /collab view/status/stop command updates with read-only participant status and join hints.
64 lines
2.3 KiB
TypeScript
64 lines
2.3 KiB
TypeScript
/**
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* AES-256-GCM sealing for collab frames.
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*
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* The room key lives only in the link fragment; the relay sees opaque bytes.
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* Sealed layout: `[12B IV][ciphertext+tag]`.
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*/
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import { ROOM_KEY_BYTES, WRITE_TOKEN_BYTES } from "@oh-my-pi/pi-wire";
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import type { CollabFrame } from "./protocol";
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const AES_ALGORITHM = "AES-GCM";
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const IV_LENGTH = 12;
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const TEXT_ENCODER = new TextEncoder();
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const TEXT_DECODER = new TextDecoder();
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export function generateRoomKey(): Uint8Array {
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const key = new Uint8Array(ROOM_KEY_BYTES);
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crypto.getRandomValues(key);
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return key;
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}
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export function generateWriteToken(): Uint8Array {
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const token = new Uint8Array(WRITE_TOKEN_BYTES);
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crypto.getRandomValues(token);
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return token;
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}
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export function importRoomKey(raw: Uint8Array): Promise<CryptoKey> {
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if (raw.byteLength !== ROOM_KEY_BYTES) {
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throw new Error(`Room key must be ${ROOM_KEY_BYTES} bytes, got ${raw.byteLength}`);
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}
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return crypto.subtle.importKey("raw", asStrict(raw), AES_ALGORITHM, false, ["encrypt", "decrypt"]);
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}
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export async function seal(key: CryptoKey, frame: CollabFrame): Promise<Uint8Array> {
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const iv = new Uint8Array(IV_LENGTH);
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crypto.getRandomValues(iv);
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const plaintext = TEXT_ENCODER.encode(JSON.stringify(frame));
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const ciphertext = new Uint8Array(await crypto.subtle.encrypt({ name: AES_ALGORITHM, iv }, key, plaintext));
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const out = new Uint8Array(IV_LENGTH + ciphertext.byteLength);
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out.set(iv, 0);
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out.set(ciphertext, IV_LENGTH);
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return out;
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}
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/** Inverse of {@link seal}. Throws on auth failure or malformed input. */
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export async function open(key: CryptoKey, data: Uint8Array): Promise<CollabFrame> {
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if (data.byteLength <= IV_LENGTH) {
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throw new Error("Sealed frame too short");
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}
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const iv = asStrict(data.subarray(0, IV_LENGTH));
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const ciphertext = asStrict(data.subarray(IV_LENGTH));
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const plaintext = new Uint8Array(await crypto.subtle.decrypt({ name: AES_ALGORITHM, iv }, key, ciphertext));
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return JSON.parse(TEXT_DECODER.decode(plaintext)) as CollabFrame;
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}
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function asStrict(bytes: Uint8Array): Uint8Array<ArrayBuffer> {
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if (bytes.buffer instanceof ArrayBuffer && bytes.byteOffset === 0 && bytes.byteLength === bytes.buffer.byteLength) {
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return bytes as Uint8Array<ArrayBuffer>;
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}
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const copy = new Uint8Array(bytes.byteLength);
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copy.set(bytes);
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return copy;
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}
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